The effect of different moisture contents at ensiling on silo degradation and digestibility of structural carbohydrates of orchardgrass

The loss of structural carbohydrates from orchardgrass (Dactylis glomerata L.) ensiled at a low (LM, 40%), medium (MM, 65%) and high moisture (HM, 76%) content was studied. The digestibility, of the four treatments (i.e. fresh material, LM, MM, and HM silages) was determined with four wethers in a 4×4 Latin square design. The fermentation quality of all silages was acceptable. The dry matter (DM) loss in all silages was also small (2–3%). The losses of water-soluble carbohydrates (WSCs), hemicellulose and gross energy increased (P<0.05) with higher moisture content at ensiling. The WSC losses were 23, 70 and 77% in LM, MM and HM silages and hemicellulose losses were 7, 9 and 12%, respectively. Lower (P<0.05) crude protein (CP) and hemicellulose digestibility were observed in HM silage. Similarly, DM, gross energy and cellulose digestibility tended to be lowered in HM silage. The digestible CP was lower (P<0.05) with higher moisture content in the silage, while the digestible energy value was decreased in silages compared to fresh orchardgrass. These results indicated that the higher moisture content of orchardgrass at ensiling gave higher losses of WSC and hemicellulose resulting in decreased digestibility. However, wilting before ensiling was efficient in reducing these losses and improved digestibility.